To create a Mac installer, first, build OpenSim:
  ./make-opensim.sh

Then open OpenSim.pmdoc in PackageMaker.  Delete OpenSim from the
contents pane on the left.  Then add your newly-built OpenSim folder
as new contents.

On the Configuration tab:
* Set destination to "/opt".
* Set Package Identifier to "com.opensimulator.opensim.pkg"
* Set version to the OpenSim version you built.
* Check "Require admin authentication"

On the Contents tab:
* Check "Include root in package"

Click "Build", save as "OpenSimulator-VERSION.mpkg".